Attention is a critical cognitive function that allows us to dynamically select and enhance the processing of the stimuli in our environment that are the most relevant or highest priority at each moment. Directing attention to a stimulus leads to lower perceptual thresholds, faster reaction times (RTs), and increased discrimination accuracy. In the previous grant period, this project used functional magnetic resonance imaging (fMRI) and scalp-recorded event-related potentials (ERPs) to investigate the neural mechanisms of attention. These included studies of the modulatory effects of attention on processing in the sensory pathways, the top-down control mechanisms that accomplish that modulation, executive and attentional processes related to stimulus conflict, and intermodal attentional processes. Another critical cognitive function is our ability to rapidly and correctly perceive stimuli and cues related to, and important for, successful social interactions. In previous work, we have also investigated the brain mechanisms underlying various aspects of social perception. This has included work focused on identifying the functions subserved by specific brain regions, including the role of the fusiform gyrus (FFG) and superior temporal sulcus (STS) regions in the processing of faces and eye gaze. In the currently proposed project, we aim to fully integrate these two lines of inquiry and investigate the neural and cognitive interactions between the systems involved in the control of visual spatial attention and those involved in social perception, particularly those related to the processing of faces, face emotion, and eye gaze. We will study these interactions both from a top-down standpoint (i.e., the influence and importance of attention on the processing of these socially relevant stimuli) and from a bottom-up standpoint (i.e., how these factors can attract, capture, and/or otherwise influence our attention). We will use both fMRI and scalp-recorded ERPs to investigate these interactions in order to delineate not only the brain areas involved in these interactions, but also the timing and sequence of their activations, thereby enhancing our understanding of the underlying mechanisms. A variety of neurological disorders, such as attention-deficit disorder, Alzheimer's disease, and autism, have adverse effects on both attentional and social perception capabilities. Traumatic brain injury following stroke can also result in dramatic impairments in attention, social perception, and affective processing. The proposed studies will provide important information that can be used to better understand these neurological disorders and develop effective treatments.